Remove content::NotificationObserver dependency from most Prefs code.

chrome/browser/browser_process_impl.h

Index: chrome/browser/browser_process_impl.h
diff --git a/chrome/browser/browser_process_impl.h b/chrome/browser/browser_process_impl.h
index b3549834937470fc65610e9821eef7d3b16f932a..abc549a208a80dc6036db8035952c5868577c371 100644
--- a/chrome/browser/browser_process_impl.h
+++ b/chrome/browser/browser_process_impl.h
@@ -17,11 +17,11 @@
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/prefs/public/pref_change_registrar.h"
+#include "base/prefs/public/pref_observer.h"
 #include "base/threading/non_thread_safe.h"
 #include "base/timer.h"
 #include "chrome/browser/api/prefs/pref_member.h"
 #include "chrome/browser/browser_process.h"
-#include "content/public/browser/notification_observer.h"
 
 class ChromeNetLog;
 class ChromeResourceDispatcherHostDelegate;
@@ -40,7 +40,7 @@ class PolicyService;
 // Real implementation of BrowserProcess that creates and returns the services.
 class BrowserProcessImpl : public BrowserProcess,
                            public base::NonThreadSafe,
-                           public content::NotificationObserver {
+                           public PrefObserver {
  public:
   explicit BrowserProcessImpl(const CommandLine& command_line);
   virtual ~BrowserProcessImpl();
@@ -115,10 +115,9 @@ class BrowserProcessImpl : public BrowserProcess,
   virtual ComponentUpdateService* component_updater() OVERRIDE;
   virtual CRLSetFetcher* crl_set_fetcher() OVERRIDE;
 
-  // content::NotificationObserver implementation.
-  virtual void Observe(int type,
-                       const content::NotificationSource& source,
-                       const content::NotificationDetails& details) OVERRIDE;
+  // PrefObserver implementation.
+  virtual void OnPreferenceChanged(PrefServiceBase* service,
+                                   const std::string& pref_name) OVERRIDE;
 
  private:
   void CreateMetricsService();